Coronal Heating by Magnetohydrodynamic Turbulence Driven by Reflected Low-Frequency Waves

Abstract

A candidate mechanism for the heating of the solar corona in open field line regions is described. The interaction of Alfvén waves, generated in the photosphere or chromosphere, with their reflections and the subsequent driving of quasi-two-dimensional MHD turbulence is considered. A nonlinear cascade drives fluctuations toward short wavelengths which are transverse to the mean field, thereby heating at rates insensitive to restrictive Alfvén timescales. A phenomenology is presented, providing estimates of achievable heating efficiency that are most favorable.

Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus

“…(2) Understand Which Heating Mechanisms Dominate as a Function of Distance from the Sun Numerous models to describe the heating and acceleration mechanisms of the Hollweg (2008), Cranmer (2000), Hollweg and Isenberg (2002), Isenberg (2001a), Galinsky and Shevchenko (2000), Marsch and Tu (2001), Kasper et al (2008 b Matthaeus et al (1999), Dmitruk et al (2002), Cranmer et al (2007), Chandran et al (2009) c Bruner (1978), Ulmschneider (1985) d Parker (1979Parker ( , 1987, Sturrock (1999), Priest et al (2002), Axford and McKenzie (1992), Cargill and Klimchuk (2004), Schrijver et al (1997), Zurbuchen et al (2002) e Scudder (1994), Pierrard and Lamy (2003) solar corona and wind have been advanced with varying degrees of success, but none is universally accepted and possibly many are valid in some subset of plasma conditions. With the correct measurements SPP can determine the relative contribution of these mechanisms in the solar wind and understand which are most important.…”

“…The Turbulent Cascade An important alternative to ion cyclotron heating is the possibility that upwardly propagating low-frequency Alfven waves are partially reflected, thereby driving a turbulent cascade through coupling to zero frequency modes (Matthaeus et al 1999;Chandran et al 2009). The cascade is expected to be quasi-perpendicular and could potentially lead to quasi-perpendicular heating.…”

Reduced magnetohydrodynamics and parallel spectral transfer

“…͑Although exceptions are possible; for example, within an RMHD model counter-propagating waves can be used to drive the turbulence. 50,56,57 ͒ Finally, we note that the definition of the hydrolike modes could be generalized somewhat by using a A (k) based upon the ͑local͒ mean field as felt by that k, rather than just the global mean field, e.g., B local ϭB 0 ϩ͗b͘ local . This would presumably be in better accord with the local physics and any wave-like attributes characteristic of the fluctuations.…”

Reflection of Alfvén waves in the corona and solar wind: An impulse function approach

“…Reflections have also acquired a particular importance in recent years because noncompressive MHD turbulence, which almost certainly plays an important role in heating the corona and solar wind, requires the presence of both Elsässer variables [e.g., Velli et al, 1989]. A particularly fruitful approach has in essence used the HO equations above, augmented by nonlinear terms which phenomenologically represent an MHD version of Kolmogorov turbulent dissipation [e.g., Cranmer and van Ballegooijen, 2005;Dmitruk et al, 2001aDmitruk et al, , 2001bDmitruk et al, , 2002Dmitruk and Matthaeus, 2003;Matthaeus et al, 1999aMatthaeus et al, , 1999bMilano et al, 2003;Oughton et al, 2001;Verdini et al, 2005]. See also related papers by Campos et al [1999], Hu et al [1999], and Marsch and Tu [1993].…”